Seed priming with nano-silica effectively ameliorates chromium toxicity in Brassica napus.

Plant yield is severely hampered by chromium (Cr) toxicity, affirming the urgent need to develop strategies to suppress its phyto-accumulation. Silicon dioxide nanoparticles (SiO NPs) have emerged as a provider of sustainable crop production and resistance to abiotic stress. But, the mechanisms by which seed-primed SiO NPs palliate Cr-accumulation and its toxic impacts in Brassica napus L. tissues remains poorly understood. To address this gap, present study examined the protective efficacy of seed priming with SiO NPs (400 mg/L) in relieving the Cr (200 µM) phytotoxicity mainly in B. napus seedlings. Results delineated that SiO NPs significantly declined the accumulation of Cr (38.7/35.9%), MDA (25.9/29.1%), HO (27.04/36.9%) and O (30.02/34.7%) contents in leaves/roots, enhanced the nutrients acquisition, leading to improved photosynthetic performance and better plant growth. SiO NPs boosted the plant immunity by upregulating the transcripts of antioxidant (SOD, CAT, APX, GR) or defense-related genes (PAL, CAD, PPO, PAO and MT-1), GSH (assists Cr-vacuolar sequestration), and modifying the subcellular distribution (enhances Cr-proportion in cell wall), thereby confer tolerance to ultrastructural damages under Cr stress. Our first evidence to establish the Cr-detoxification by seed-primed SiO NPs in B. napus, indicated the potential of SiO NPs as stress-reducing agent for crops grown in Cr-contaminated areas.